Abstract: A child's play box includes a pliable base piece and four semi- rigid, planar sidewalls. The base piece has four edges, and each sidewall is joined to the base piece by a folding joint that permits the sidewall to pivot with respect to the base piece. Furthermore, each sidewall is joined to adjacent sidewalls by folding joints that permit the adjacent sidewalls to pivot with respect to each other. The folding joints collectively allow the play box to be manipulated between an open configuration in which the sidewalls extend perpendicularly from the base piece to define an internal cavity and a closed configuration in which all of the sidewalls are arranged in a stack.